No I'm not joking. Both handle bar "grips" are the same dia. on the outside In order to fit the twist grip on the right handle bar the end has to be smaller or the grip thinnerto accommodate the slip on twist grip.... The left grip is just rubber and fits over the plain bar end.

Next time you are in a bike shop look at replacement grips, one is thicker than the other.

__________________"Democracy is two wolves and a lamb voting on what to have for lunch.Liberty is a well-armed lamb contesting the vote" Ben FranklinCurrent bikes F800GS-EXCF350-Versys-690R-RZ350

I haven't had one apart in a while but thats the way they used to be on motorcycles. Maybe that was on the Harley Davidsons I used to ride. Or it could be I'm just old and full of sh!t..

I think the last idea is right. I've mechaniced on bikes, including HD's for 40+ years and have never seen or heard of a set of bars being different sized from side to side. (but I’m sure someone here will come up with some)

__________________"Democracy is two wolves and a lamb voting on what to have for lunch.Liberty is a well-armed lamb contesting the vote" Ben FranklinCurrent bikes F800GS-EXCF350-Versys-690R-RZ350

I think the last idea is right. I've mechaniced on bikes, including HD's for 40+ years and have never seen or heard of a set of bars being different sized from side to side. (but I’m sure someone here will come up with some)

I started riding in 1958. I got my first Harley in 1960. I built restored them and Hondas for a number of years. Its been a while since I worked on them. I remember some bikes back in the day that were like that. I can't say which ones. The memory just stuck in my mind. I guess I had a senior moment and need to know what I am talking about. No need to take it further.

My time in the spot light has long passed. I'm just trying to enjoy retirement and my memories.

My first choice would be to rig up a push throttle on the left side. Another possibility on a scooter with no other foot controls is to rig up a gas pedal. It works great on a car. And on a scooter with its automatic clutch it would be stomp and go!

The only bike I know of are really old ones . British ones once were like this etc I think. Don't see why an old thumb type throttle might not work . The kind you found on 3 wheel ATV from 1980.

__________________
Life's journey is not to arrive at the grave safely in a well preserved body,but rather to skid in sideways totally worn out shouting WHAT A RUSH, WHAT A RIDE.
"Life is a tragedy when seen in close-up, but a comedy in long-shot." Charlie Chaplin